Subsequent Events - Royalty Trust Distributions (Details) (Subsequent Event, USD $) In Thousands, unless otherwise specified	Jan. 29, 2015
Royalty Trusts
Subsequent Event [Line Items]
Total Distribution	$ 50,204
Amount to be Distributed to Third-Party Unitholders	43,716
Mississippian Trust I
Subsequent Event [Line Items]
Total Distribution	8,538
Amount to be Distributed to Third-Party Unitholders	6,242
Permian Trust
Subsequent Event [Line Items]
Total Distribution	27,681
Amount to be Distributed to Third-Party Unitholders	25,830
Mississippian Trust II
Subsequent Event [Line Items]
Total Distribution	13,985
Amount to be Distributed to Third-Party Unitholders	$ 11,644